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The major genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) is a C9orf72 G 4 C 2 repeat expansion 1 , 2 . Proposed mechanisms by which the expansion causes c9FTD/ALS include toxicity from repeat-containing RNA and from dipeptide repeat proteins translated from these transcripts. To investigate the contribution of poly(GR) dipeptide repeat proteins to c9FTD/ALS pathogenesis in a mammalian in vivo model, we generated mice that expressed GFP–(GR) 100 in the brain. GFP–(GR) 100 mice developed age-dependent neurodegeneration, brain atrophy, and motor and memory deficits through the accumulation of diffuse, cytoplasmic poly(GR). Poly(GR) co-localized with ribosomal subunits and the translation initiation factor eIF3η in GFP–(GR) 100 mice and, of importance, in c9FTD/ALS patients. Combined with the differential expression of ribosome-associated genes in GFP–(GR) 100 mice, these findings demonstrate poly(GR)-mediated ribosomal distress. Indeed, poly(GR) inhibited canonical and non-canonical protein translation in HEK293T cells, and also induced the formation of stress granules and delayed their disassembly. These data suggest that poly(GR) contributes to c9FTD/ALS by impairing protein translation and stress granule dynamics, consequently causing chronic cellular stress and preventing cells from mounting an effective stress response. Decreasing poly(GR) and/or interrupting interactions between poly(GR) and ribosomal and stress granule-associated proteins may thus represent potential therapeutic strategies to restore homeostasis. ALS/FTD-related C9orf72 dipeptide-repeat proteins inhibit protein translation and impair stress granule dynamics, and they cause motor and cognitive deficits in mice.

A repeat expansion in the chromosome 9 open reading frame 72 ( C9orf72 ) gene is the most common known cause of two neurodegenerative diseases: frontotemporal dementia and amyotrophic lateral sclerosis. This expansion leads to the abnormal production of proteins of repeating dipeptides, but their contribution to disease pathogenesis remains unclear. Zhang et al. engineered a mouse model to study the consequences of one of these dipeptides—prolinearginine dipeptide repeat protein, poly(PR)—in the brain. They found that poly(PR) caused neuron loss as well as motor and memory impairments. These detrimental effects resulted from poly(PR)-induced perturbation of heterochromatin function, a tightly packed form of DNA that represses gene expression. Science , this issue p. eaav2606 Poly(PR) causes neurodegeneration in vivo by inducing repetitive element expression and double-stranded RNA accumulation. How hexanucleotide GGGGCC (G 4 C 2 ) repeat expansions in C9orf72 cause frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) is not understood. We developed a mouse model engineered to express poly(PR), a proline-arginine (PR) dipeptide repeat protein synthesized from expanded G 4 C 2 repeats. The expression of green fluorescent protein–conjugated (PR) 50 (a 50-repeat PR protein) throughout the mouse brain yielded progressive brain atrophy, neuron loss, loss of poly(PR)-positive cells, and gliosis, culminating in motor and memory impairments. We found that poly(PR) bound DNA, localized to heterochromatin, and caused heterochromatin protein 1α (HP1α) liquid-phase disruptions, decreases in HP1α expression, abnormal histone methylation, and nuclear lamina invaginations. These aberrations of histone methylation, lamins, and HP1α, which regulate heterochromatin structure and gene expression, were accompanied by repetitive element expression and double-stranded RNA accumulation. Thus, we uncovered mechanisms by which poly(PR) may contribute to the pathogenesis of C9orf72 -associated FTD and ALS.

Some cases of Alzheimer's Disease (AD) and Frontotemporal Dementia (FTD) feature the mislocalization of the normally nuclear TAR DNA binding protein (TDP-43) to the cytoplasm where it is incorporated into inclusions in affected brain regions. TDP-43 plays a crucial role in the suppression of cryptic exons in the mature RNA of many targets in both AD and FTD. One such target, Stathmin-2 (STMN2), is misspliced in the absence of TDP-43 leading to a reduction of STMN2 RNA and protein while the levels of the cryptic splice variant is increased. Cryptic exons are not conserved across species, meaning previous Tdp-43 models did not capture Stmn2 processing defects and Stmn2 loss of function (LOF). We hypothesize that STMN2 LOF contributes to cognitive phenotypes observed in AD and FTD. We have generated a novel mouse that more accurately models human disease mechanisms by expressing short-hairpin (shRNA) via adeno associated virus in the central nervous system of a recently described humanized Stmn2 mouse model in which Stmn2 splicing is dependent on Tdp-43. In this mouse we will simultaneously model Tdp-43 loss of function and aberrant Stmn2 splicing. Our preliminary experiments demonstrate that humanized Stmn2 mice expressing shRNA against Tardbp have a reduction of Tardbp RNA and TDP-43 protein compared to mice expressing a non-targeting shRNA. Tdp-43 knock-down is accompanied by cryptic splicing of endogenous mouse targets, Sortilin 1 and Translin. As anticipated, we also detected cryptic Stmn2 splicing, suggesting that correct Stmn2 splicing is dependent on Tdp-43 in this model. We will further characterize motor and cognitive functions in addition to neurodegeneration and gliosis in these animals. We anticipate this novel model, and our subsequent studies will identify relevant disease mechanisms and provide an invaluable tool with which to investigate therapies for AD and FTD.

Background Some cases of Alzheimer's Disease (AD) and Frontotemporal Dementia (FTD) feature the mislocalization of the normally nuclear TAR DNA binding protein (TDP‐43) to the cytoplasm where it is incorporated into inclusions in affected brain regions. TDP‐43 plays a crucial role in the suppression of cryptic exons in the mature RNA of many targets in both AD and FTD. One such target, Stathmin‐2 (STMN2), is misspliced in the absence of TDP‐43 leading to a reduction of STMN2 RNA and protein while the levels of the cryptic splice variant is increased. Cryptic exons are not conserved across species, meaning previous Tdp‐43 models did not capture Stmn2 processing defects and Stmn2 loss of function (LOF). We hypothesize that STMN2 LOF contributes to cognitive phenotypes observed in AD and FTD. Method We have generated a novel mouse that more accurately models human disease mechanisms by expressing short‐hairpin (shRNA) via adeno associated virus in the central nervous system of a recently described humanized Stmn2 mouse model in which Stmn2 splicing is dependent on Tdp‐43. In this mouse we will simultaneously model Tdp‐43 loss of function and aberrant Stmn2 splicing. Result Our preliminary experiments demonstrate that humanized Stmn2 mice expressing shRNA against Tardbp have a reduction of Tardbp RNA and TDP‐43 protein compared to mice expressing a non‐targeting shRNA. Tdp‐43 knock‐down is accompanied by cryptic splicing of endogenous mouse targets, Sortilin 1 and Translin. As anticipated, we also detected cryptic Stmn2 splicing, suggesting that correct Stmn2 splicing is dependent on Tdp‐43 in this model. We will further characterize motor and cognitive functions in addition to neurodegeneration and gliosis in these animals. Conclusion We anticipate this novel model, and our subsequent studies will identify relevant disease mechanisms and provide an invaluable tool with which to investigate therapies for AD and FTD.

Amyotrophic lateral sclerosis (ALS) is a fatal disease, characterized by the selective loss of motor neurons leading to paralysis. Mutations in the gene encoding superoxide dismutase 1 (SOD1) are the second most common cause of familial ALS, and considerable evidence suggests that these mutations result in an increase in toxicity due to protein misfolding. We previously demonstrated in the SOD1G93A rat model that misfolded SOD1 exists as distinct conformers and forms deposits on mitochondrial subpopulations. Here, using SOD1G93A rats and conformation-restricted antibodies specific for misfolded SOD1 (B8H10 and AMF7-63), we identified the interactomes of the mitochondrial pools of misfolded SOD1. This strategy identified binding proteins that uniquely interacted with either AMF7-63 or B8H10-reactive SOD1 conformers as well as with a high proportion of interactors common to both conformers. Of this latter set, we identified the E3 ubiquitin ligase TNF receptor-associated factor 6 (TRAF6) as a SOD1 interactor and determined that exposure of the SOD1 functional loops facilitates this interaction. Of note, this conformational change was not universally fulfilled by all SOD1 variants and differentiated TRAF6-interacting from TRAF6 non-interacting SOD1 variants. Functionally, TRAF6 stimulated polyubiquitination and aggregation of the interacting SOD1 variants. TRAF6 E3 ubiquitin ligase activity was required for the former, but was dispensable for the latter, indicating that TRAF6-mediated polyubiquitination and aggregation of the SOD1 variants are independent events. We propose that the interaction between misfolded SOD1 and TRAF6 may be relevant to the etiology of ALS. Footnotes * New data in Figure 3. Text and figures have been modified in accordance with reviewers comments.

It is not known whether early intervention can improve long-term autism symptom outcomes. We aimed to follow-up the Preschool Autism Communication Trial (PACT), to investigate whether the PACT intervention had a long-term effect on autism symptoms and continued effects on parent and child social interaction. PACT was a randomised controlled trial of a parent-mediated social communication intervention for children aged 2–4 years with core autism. Follow-up ascertainment was done at three specialised clinical services centres in the UK (London, Manchester, and Newcastle) at a median of 5·75 years (IQR 5·42–5·92) from the original trial endpoint. The main blinded outcomes were the comparative severity score (CSS) from the Autism Diagnostic Observation Schedule (ADOS), the Dyadic Communication Assessment Measure (DCMA) of the proportion of child initiatiations when interacting with the parent, and an expressive-receptive language composite. All analyses followed the intention-to-treat principle. PACT is registered with the ISRCTN registry, number ISRCTN58133827. 121 (80%) of the 152 trial participants (59 [77%] of 77 assigned to PACT intervention vs 62 [83%] of 75 assigned to treatment as usual) were traced and consented to be assessed between July, 2013, and September, 2014. Mean age at follow-up was 10·5 years (SD 0·8). Group difference in favour of the PACT intervention based on ADOS CSS of log-odds effect size (ES) was 0·64 (95% CI 0·07 to 1·20) at treatment endpoint and ES 0·70 (95% CI −0·05 to 1·47) at follow-up, giving an overall reduction in symptom severity over the course of the whole trial and follow-up period (ES 0·55, 95% CI 0·14 to 0·91, p=0·004). Group difference in DCMA child initiations at follow-up showed a Cohen's d ES of 0·29 (95% CI −0.02 to 0.57) and was significant over the course of the study (ES 0·33, 95% CI 0·11 to 0·57, p=0·004). There were no group differences in the language composite at follow-up (ES 0·15, 95% CI −0·23 to 0·53). The results are the first to show long-term symptom reduction after a randomised controlled trial of early intervention in autism spectrum disorder. They support the clinical value of the PACT intervention and have implications for developmental theory. Medical Research Council.

All coronaviruses known to have recently emerged as human pathogens probably originated in bats 1 . Here we use a single experimental platform based on immunodeficient mice implanted with human lung tissue (hereafter, human lung-only mice (LoM)) to demonstrate the efficient in vivo replication of severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as well as two endogenous SARS-like bat coronaviruses that show potential for emergence as human pathogens. Virus replication in this model occurs in bona fide human lung tissue and does not require any type of adaptation of the virus or the host. Our results indicate that bats contain endogenous coronaviruses that are capable of direct transmission to humans. Our detailed analysis of in vivo infection with SARS-CoV-2 in human lung tissue from LoM showed a predominant infection of human lung epithelial cells, including type-2 pneumocytes that are present in alveoli and ciliated airway cells. Acute infection with SARS-CoV-2 was highly cytopathic and induced a robust and sustained type-I interferon and inflammatory cytokine and chemokine response. Finally, we evaluated a therapeutic and pre-exposure prophylaxis strategy for SARS-CoV-2 infection. Our results show that therapeutic and prophylactic administration of EIDD-2801—an oral broad-spectrum antiviral agent that is currently in phase II/III clinical trials—markedly inhibited SARS-CoV-2 replication in vivo, and thus has considerable potential for the prevention and treatment of COVID-19. Human and bat coronaviruses replicate efficiently in immunodeficient mice implanted with human lung tissue, and treatment or prophylaxis using EIDD-2801 in this model suggests that this oral antiviral agent may be effective in preventing COVID-19.

The badlands of Dinosaur Provincial Park (Alberta, Canada) are renowned for the exceptional abundance and diversity of Campanian-aged vertebrate body fossils, especially dinosaurs. Due to the steep exposures and rapid erosion, dinosaur tracks and trackways are considered extremely rare but have been recorded from a small number of concretionary casts, which pertain to hadrosaurids and a single tyrannosaurid. Here, we document the first multitaxic dinosaur footprint assemblage from the Dinosaur Park Formation based on a new locality that contains multiple individual ceratopsids, two tyrannosaurids, a possible ankylosaurian, and a small theropod-like taxon. Ceratopsid tracks are globally rare but dominate the new tracksite, suggesting gregarious behaviour, which is also supported by their regular spacing and parallel arrangement. The possible ankylosaurian track is identified (in part) on account of having three distinct pedal digits, consistent with the pedal anatomy of several Dinosaur Park ankylosaurids ( Euoplocephalus, Dyoplosaurus ) and the newly erected ichnotaxon Ruopodosaurus clava but differentiating it from other ankylosaurian tracks ( Tetrapodosaurus isp.). Importantly, the new tracks are the first natural moulds (concave epirelief) found in Dinosaur Provincial Park, which, due to the unique geomorphology of the area, can only be recognised in outcrops where there are prominent sediment displacement rims. The new search image outlined here has already resulted in several subsequent trackway discoveries, and has the potential to transform ichnological studies in the Dinosaur Park Formation and related formations where badlands prevail.

Background Inclusions of TAR DNA-binding protein 43 kDa (TDP-43) has been designated limbic-predominant, age-related TDP-43 encephalopathy (LATE), with or without co-occurrence of Alzheimer’s disease (AD). Approximately, 30–70% AD cases present TDP-43 proteinopathy (AD-TDP), and a greater disease severity compared to AD patients without TDP-43 pathology. However, it remains unclear to what extent TDP-43 dysfunction is involved in AD pathogenesis. Methods To investigate whether TDP-43 dysfunction is a prominent feature in AD-TDP cases, we evaluated whether non-conserved cryptic exons, which serve as a marker of TDP-43 dysfunction in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD-TDP), accumulate in AD-TDP brains. We assessed a cohort of 192 post-mortem brains from three different brain regions: amygdala, hippocampus, and frontal cortex. Following RNA and protein extraction, qRT-PCR and immunoassays were performed to quantify the accumulation of cryptic RNA targets and phosphorylated TDP-43 pathology, respectively. Results We detected the accumulation of misspliced cryptic or skiptic RNAs of STMN2 , KCNQ2 , UNC13A , CAMK2B , and SYT7 in the amygdala and hippocampus of AD-TDP cases. The topographic distribution of cryptic RNA accumulation mimicked that of phosphorylated TDP-43, regardless of TDP-43 subtype classification. Further, cryptic RNAs efficiently discriminated AD-TDP cases from controls. Conclusions Overall, our results indicate that cryptic RNAs may represent an intriguing new therapeutic and diagnostic target in AD, and that methods aimed at detecting and measuring these species in patient biofluids could be used as a reliable tool to assess TDP-43 pathology in AD. Our work also raises the possibility that TDP-43 dysfunction and related changes in cryptic splicing could represent a common molecular mechanism shared between AD-TDP and FTLD-TDP.

AbstractObjectiveTo determine if guided internet based cognitive behavioural therapy with a trauma focus (CBT-TF) is non-inferior to individual face-to-face CBT-TF for mild to moderate post-traumatic stress disorder (PTSD) to one traumatic event.DesignPragmatic, multicentre, randomised controlled non-inferiority trial (RAPID).SettingPrimary and secondary mental health settings across the UK’s NHS.Participants196 adults with a primary diagnosis of mild to moderate PTSD were randomised in a 1:1 ratio to one of two interventions, with 82% retention at 16 weeks and 71% retention at 52 weeks. 19 participants and 10 therapists were purposively sampled and interviewed for evaluation of the process.InterventionsUp to 12 face-to-face, manual based, individual CBT-TF sessions, each lasting 60-90 minutes; or guided internet based CBT-TF with an eight step online programme, with up to three hours of contact with a therapist and four brief telephone calls or email contacts between sessions.Main outcome measuresPrimary outcome was the Clinician Administered PTSD Scale for DSM-5 (CAPS-5) at 16 weeks after randomisation (diagnosis of PTSD based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, DSM-5). Secondary outcomes included severity of PTSD symptoms at 52 weeks, and functioning, symptoms of depression and anxiety, use of alcohol, and perceived social support at 16 and 52 weeks after randomisation.ResultsNon-inferiority was found at the primary endpoint of 16 weeks on the CAPS-5 (mean difference 1.01, one sided 95% confidence interval −∞ to 3.90, non-inferiority P=0.012). Improvements in CAPS-5 score of more than 60% in the two groups were maintained at 52 weeks, but the non-inferiority results were inconclusive in favour of face-to-face CBT-TF at this time point (3.20, −∞ to 6.00, P=0.15). Guided internet based CBT-TF was significantly (P<0.001) cheaper than face-to-face CBT-TF and seemed to be acceptable and well tolerated by participants. The main themes of the qualitative analysis were facilitators and barriers to engagement with guided internet based CBT-TF, treatment outcomes, and considerations for its future implementation.ConclusionsGuided internet based CBT-TF for mild to moderate PTSD to one traumatic event was non-inferior to individual face-to-face CBT-TF and should be considered a first line treatment for people with this condition.Trial registrationISRCTN13697710.